One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(7,11)(10,12)(13,14,18,22,19,21,27,26)(15,23,24,28,25,16,20,17)(5,6)(7,10)(8,9)(11,12)(13,15,19,25)(14,17,21,28)(16,26,23,22)(18,20,27,24)(2,4)(6,9)(10,12)(13,16)(14,20)(15,22)(17,18)(19,23)(21,24)(25,26)(27,28) involution — undirected(6,9)(10,12)(13,17)(14,15)(16,27)(18,23)(19,28)(20,26)(21,25)(22,24) involution — undirected(5,7,8,11)(6,10,9,12)(14,21)(16,23)(17,28)(22,26)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.